JP3502129B2 - Cyclohexane dimethyl derivative - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cyclohexanedimethyl derivative useful as an electro-optical display material.
The present invention relates to a cyclohexanedimethyl derivative which can give a liquid crystal composition having low refractive index anisotropy (Δn) and high dielectric constant anisotropy (Δε) when mixed with a nematic liquid crystal material. 2. Description of the Related Art Physical properties required of a liquid crystal material include a liquid crystal state which is stable to water, light and heat, has a low threshold voltage, and can be used in a wide temperature range including room temperature. It is desired that However, in general, it is difficult to satisfy all the required performances with a single liquid crystal compound, and a composition closer to the required performance is used by mixing several types of liquid crystal compounds and compounds other than liquid crystal. In general, the threshold voltage of a field-effect liquid crystal display device using a liquid crystal composition having a positive dielectric anisotropy (Δε) (hereinafter simply referred to as “Δε”) is determined by the Δε of the composition. Is known to be inversely proportional to the square root of. In particular, in recent years, twisted nematic (TN) liquid crystal devices are mainly driven by a battery, and for this purpose, a liquid crystal material having a particularly low threshold voltage is required, and the use of a liquid crystal material having a large positive Δε is important. become. Further, the anisotropy (Δn) of the refractive index (hereinafter sometimes simply referred to as “Δn”) affects the visual characteristics of the liquid crystal display element, and the smaller the Δn, the better the visual characteristics. It is preferable to mix them with a nematic liquid crystal material to reduce Δn or to maintain a small value. For example, Japanese Patent Application Laid-Open No. Sho 59-80485 proposes trans-4-alkylcyclohexylmethyl 4-cyanophenyl ethers as a liquid crystal material having a high Δε, but shows only an insufficient effect. Without, for example, JP-A-54-157541,
JP-A-56-140944, JP-A-56-161
339, JP-A-57-146729, JP-A-1-502274, JP-A-2-272888 and the like have proposed various p-alkylcyclohexylmethoxybenzene derivatives. Similarly, the effect of increasing Δε was still insufficient. Accordingly, an object of the present invention is to provide an anisotropic material having a low refractive index (Δ
An object of the present invention is to provide a compound capable of providing a liquid crystal composition having n) and anisotropy (Δε) having a high dielectric constant. [0007] In view of the present situation, the present inventors have made various studies, and as a result, have found that a specific cyclohexanedimethyl derivative can achieve the above object. Reached. That is, the present invention provides a cyclohexanedimethyl derivative represented by the following general formula (I) [formula 2] (same as the above [formula 1]). [0009] Hereinafter, the cyclohexanedimethyl derivative of the present invention will be described in detail. In the general formula (I), examples of the alkyl group having 1 to 12 carbon atoms represented by R ₁ include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, Tert-butyl, n-pentyl, 2-
Methylbutyl, 3-methylbutyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, n-octyl, 2-ethylhexyl, isooctyl, 2-octyl, n-nonyl, isononyl, n-decyl, isodecyl, n-undecyl, isoundecyl, n-dodecyl,
And groups such as isododecyl. X ₁ , X ₂ and X ₃
Examples of the halogen atom represented by include chlorine, fluorine, and bromine. Accordingly, the cyclohexanedimethyl derivative of the present invention includes, for example, compounds Nos. 1 to 9 of the following [Chemical Formula 3] to [Chemical Formula 11]. [0013] Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image The cyclohexanedimethyl derivative of the present invention is obtained, for example, by alkyl etherifying 1,4-cyclohexanedimethanol using an alkali metal hydride and an alkyl halide to synthesize 4-alkoxymethylcyclohexylmethanol, which is then reacted with a nucleus. It can be easily produced by etherifying a substituted phenol in a conventional manner. By mixing the cyclohexanedimethyl derivative of the present invention with a known liquid crystal material (base liquid crystal),
The dielectric anisotropy (Δε) can be increased without changing the refractive index anisotropy (Δn) of the liquid crystal material. The compound constituting the mother liquid crystal includes, for example, compounds shown in the following [Chemical Formula 12]. The mother liquid crystal is usually used by mixing several or more of these compounds. Embedded image Therefore, specific examples of the nematic liquid crystal compounds represented by the above general formulas (1) to (3) include the following compounds of the following [Formula 13]. Embedded image The amount of the cyclohexanedimethyl derivative of the present invention is preferably 1 to 30 parts by weight based on 100 parts by weight of the mother liquid crystal. The production methods and properties of the compounds of the present invention will be described in more detail with reference to the following examples. However, the invention is not limited at all by these examples. Example 1 Synthesis of trans-4-methoxymethylcyclohexylmethyl-4-cyanophenyl ether (compound No. 1 of the above formula (1)) (1) Synthesis of trans-4-methoxymethylcyclohexylmethanol Sodium (55% oily)
5 g was dispersed in 1 liter of N, N'-dimethylformamide, and a solution of 259.6 g of trans-1,4-cyclohexanedimethanol dissolved in 500 ml of N, N'-dimethylformamide was added dropwise. After stirring at room temperature for 3 hours, the mixture was left overnight. Thereafter, a solution prepared by dissolving 212.9 g of methyl iodide in 100 ml of N, N'-dimethylformamide was added dropwise to the left solution, and the mixture was stirred at room temperature for 4 hours, and the precipitate was separated by filtration. After removing the solvent from the filtrate, 1 liter of water was added, and the mixture was extracted with ethyl acetate. After drying and removing the solvent, the product was subjected to silica gel column treatment using ethyl acetate / n-hexane (1/2) as a developing solvent, to obtain 122.2 g of trans-4-methoxymethylcyclohexylmethanol (yield: 51%). ) Got. (2) Synthesis of trans-4-methoxymethylcyclohexylmethyl-4-cyanophenyl ether 1.60 g of trans-4-methoxymethylcyclohexylmethanol obtained in (1), 1.79 g of 4-hydroxybenzonitrile and 1.79 g of 4-hydroxybenzonitrile Triphenylphosphine3.
14 g was dissolved in 20 ml of dry diethyl ether. 2.42 g of diisopropyl azodicarboxylate was added dropwise thereto, and the mixture was stirred at room temperature for 2 hours, and the precipitated triphenylphosphine oxide was separated by filtration. After removing the solvent from the filtrate, the product was subjected to silica gel column treatment using ethyl acetate / n-hexane (2/8) as a developing solvent, and recrystallized from n-hexane to give white crystals having a melting point of 79.6 ° C. 95 g (yield 50
%). The results of infrared spectroscopy of the obtained white crystals are as follows, and it was confirmed that the white crystals were the target product. 2900cm ^-1, 2840cm ^-1, 2200cm
^{-1, 1600cm -1, 1500cm -1,} 1260c
m ^-1 , 1170 cm ^-1 , 1020 cm ^-1 , 830 cm ^-1 The characteristic values of the obtained object are as follows: the anisotropy of refractive index (Δn) (25 ° C.) is 0.118; Has an anisotropy (Δε) (25 ° C.) of 21.2, indicating that Δε shows an extremely high value. On the other hand, a comparative compound of the following formula [Chemical Formula 14] having the same structure except that the methoxymethyl group of the compound No. 1 was replaced with an n-propyl group was anisotropic in refractive index (Δ
n) (25 ° C.) 0.111, dielectric anisotropy (Δε)
(25 ° C.) was 10.5, and the value of Δn was about the same, whereas the value of Δε was only about half the size of Compound No. 1. Embedded image Example 2: Synthesis of trans-4-methoxymethylcyclohexylmethyl-3,4-difluorophenyl ether (compound No. 6 of the above-mentioned [Chemical Formula 8]) The trans obtained in Example 1 (1) 2.84 g of -4-methoxymethylcyclohexylmethanol, 2.38 g of 3,4-difluorophenol and 5.67 g of triphenylphosphine were dissolved in 23 ml of dry tetrahydrofuran. To this, diisopropyl azodicarboxylate 4.3
7 g was added dropwise, and after stirring at room temperature for 0.5 hour, the precipitated triphenylphosphine oxide was separated by filtration. After the filtrate was desolvated, the product was subjected to a silica gel column treatment using ethyl acetate / n-hexane (1/2) as a developing solvent, and further subjected to 1 step.
Vacuum distillation was performed at 40 to 150 ° C./0.8 mmHg to obtain 3.98 g of a colorless and transparent liquid (81% yield). The results of infrared spectroscopy of the obtained liquid are as follows, and it was confirmed that the liquid was the target substance. 2910cm ^-1 , 2850cm ^-1 , 1600c
m ⁻¹ , 1510 cm ⁻¹ , 1210 cm ⁻¹ , 1160 cm
^{-1, 1100cm -1, 1030cm -1,} 775cm -1 Further, the characteristic values of the resultant target product, the anisotropy of refractive index (Δn) (25 ℃) 0.035, the dielectric constant It can be seen that the anisotropy (Δε) (25 ° C.) is 7.2 and Δε shows an extremely high value. As is apparent from Examples 1 and 2, the cyclohexanedimethyl derivative of the present invention has the same Δn and a remarkably high Δε as compared with the known compound in which the terminal akoxymethyl group is converted to an alkyl group. You can see that. The cyclohexanedimethyl derivative of the present invention is a liquid crystal material having a relatively low refractive index anisotropy (Δn), a high dielectric anisotropy (Δε), and a nematic liquid crystal. By mixing with the material, the low refractive index anisotropy (Δ
n) and a liquid crystal composition having high dielectric constant anisotropy (Δε).

Continuation of the front page (72) Inventor Toshihiko Murai 5-2-13-1 Shirahata, Urawa-shi, Saitama Asahi Denka Kogyo Co., Ltd. (56) References JP-A-5-125008 (JP, A) JP-A-7- 56132 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claim 1] A cyclohexanedimethyl derivative represented by the following general formula (I): Embedded image